1. Field of the Invention
The present invention generally relates to a carrier mechanism, and in particular to a carrier mechanism for supporting and moving a travelling module of an optic scanner.
2. Description of the Prior Art
An image scanning device or optic scanner generally comprises an optic scanning module movable by a driving module between a forward position and a rearward position for scanning a document to be scanned. FIG. 1 of the attached drawings shows an example of a conventional flat-bed optic scanner, mainly comprising a casing 11, a document support plate 12, an optic scanning module 13, a pair of guide rods 14a, 14b, and a driving mechanism.
The guide rods 14a, 14b are parallel to and spaced from each other. The driving mechanism includes a driving motor 15 and a transmission belt or a gear train 16 mechanically coupled to the optic scanning module 13 for driving the scanning module 13 between the forward and rearward positions.
The driving mechanism of the conventional optic scanner requires a complicated structure including a number of parts. This increases costs of manufacture and maintenance. Furthermore, the prior art suffer a problem that the driving mechanism is integrated with the scanning module. This causes difficulty in making modification of the scanning module for the driving mechanism that is integrated with the scanning module has to be redesigned in order to be compatible with the modified scanning module.
It is thus desirable to provide a carrier mechanism for an optic scanner to overcome the above problems.
Accordingly, an object of the present invention is to provide a carrier mechanism for supporting and moving a travelling module. By means of the carrier mechanism, the travelling module may be supported and moved between a forward position and a rearward position along a predetermined travelling path.
The other object of the present invention is to provide a carrier mechanism to which an image scanning module is removably mounted whereby the image scanning module may be replaced by another scanning module of different specification without modifying the carrier mechanism.
Another object of the present invention is to provide a supporting and driving mechanism for an image scanning module of an optic scanner having a simplified structure and thus required fewer parts and reduced cost.
To achieve the above objects, in accordance with the present invention, there is provided a carrier mechanism for a travelling module. The travelling module is supported by the carrier mechanism and movable along a predetermined travelling path. In a preferred embodiment of the present invention, the travelling module is an image scanning module of an optic scanner. The carrier mechanism is mounted inside a casing of the optic scanner for supporting and moving the image scanning module in a predetermined direction between forward and rearward positions. The carrier mechanism comprises a guide device fixed inside the casing, a carrier movable along the guide device between the forward and rearward positions with the scanning module removably mounted on the carrier and a driving mechanism comprising a motor mounted to the carrier and in driving engagement with the guide device for moving the carrier between the forward and rearward positions. The guide device comprises an elongate strip integrally formed on a bottom of the casing with a rack formed along a side face thereof to drivingly engage a pinion of the motor. Alternatively, a timing belt and toothed wheel system or a wire and pulley system or a worm and gear system may be used to replace the pinion and rack system.